Method for forming rivet joints

Abstract

A method and apparatus for forming rivet joints with a desired amount of clearance to allow pivotal motion of the parts interconnected by such joints. Parts to be riveted together are aligned with each other, and a rivet is placed into aligned holes. A parts clamp urges the parts and a preformed head of the rivet against a rivet support anvil to establish an initial condition. A parts support anvil is placed in a required position with respect to the rivet support anvil prior to formation of the second head on the opposite end of the rivet, to provide the desired amount of clearance. The parts support anvil is moved by pushing against a set of arched leaf springs to adjust their effective length, using a hydraulic motor controlled in response to an electrical signal from a transducer that measures movement of parts by the parts support anvil.

What is claimed is:  
     
       1. A method of riveting a plurality of parts together to form an assembly with a predetermined clearance or interference between a rivet and said plurality of parts interconnected by said rivet, comprising: 
       (a) providing a rivet support anvil mounted fixedly on a supporting structure;  
       (b) providing a parts clamp supported movably on said supporting structure;  
       (c) placing a rivet having a preformed first head into a rivet hole extending through said plurality of parts to be riveted together, leaving said preformed first head on a first side of said plurality of parts to be riveted together;  
       (d) urging said parts clamp against a second side of said plurality of parts to be riveted together, thereby urging said preformed first head against a rivet support anvil and urging said rivet into said rivet hole and into contact against said first side of said plurality of parts, thereby establishing a reference position of said parts clamp;  
       (e) thereafter urging a parts support anvil from an initial position with respect to said rivet support anvil into pushing engagement with said first side of said plurality of parts, thereby displacing said parts clamp to an adjusted position with respect to said reference position and said parts support anvil to an adjusted position with respect to said initial position; and  
       (f) thereafter forming a second head on said rivet while retaining said parts support anvil in said adjusted position with respect to said rivet support anvil.  
     
     
       2. The method of  claim 1  wherein said step of urging said parts support anvil includes moving said parts support anvil with respect to said rivet support. 
     
     
       3. The method of  claim 1  wherein said step of urging said parts support anvil includes moving said parts clamp by a predetermined distance relative to said rivet support anvil and said supporting structure. 
     
     
       4. The method of  claim 1  wherein said step of urging said parts support anvil includes revising an amount of curvature in a leaf spring extending between said supporting structure and said parts support anvil, thereby lengthening said leaf spring and urging said parts support anvil in a direction toward said first side of said plurality of parts. 
     
     
       5. The method of  claim 4  wherein said step of revising said curvature of said leaf spring moves said parts support anvil toward said first side of said plurality of parts. 
     
     
       6. The method of  claim 4 , including providing a plurality of said leaf springs arranged closely alongside one another in a group and simultaneously revising said amount of curvature of all of said leaf springs. 
     
     
       7. A method of riveting a plurality of parts together to form an assembly with a predetermined clearance or interference between a rivet and said plurality of parts interconnected by said rivet, comprising: 
       (a) providing a rivet support anvil mounted fixedly on a supporting structure;  
       (b) providing a parts clamp supported movably on said supporting structure;  
       (c) placing a rivet having a preformed first head into a rivet hole extending through said plurality of parts to be riveted together, leaving said preformed first head on a first side of said plurality of parts to be riveted together;  
       (d) urging said parts clamp toward a second side of said plurality of parts to be riveted together, thereby urging said preformed first head against said rivet support anvil and urging said rivet into said rivet hole;  
       (e) placing a parts support anvil into contact with said first side of said plurality of parts adjacent said rivet support anvil;  
       (f) thereafter adjusting said parts support anvil with respect to said rivet support anvil by revising an amount of curvature in a leaf spring extending between said supporting structure and said parts support anvil, using a hydraulic motor to move a portion of said leaf spring, thereby partially straightening and lengthening said leaf spring and urging said parts support anvil in a direction toward said first side of said plurality of parts, thereby creating an adjusted condition; and  
       (g) thereafter forming a second head on said rivet while retaining said parts support anvil in the adjusted condition with respect to said rivet support anvil.  
     
     
       8. The method of  claim 7 , including the step of thereafter preventing flow of hydraulic fluid in said hydraulic motor and thereby maintaining said leaf spring in a partially straightened condition during said step of forming a second head on said rivet.